There is an image forming apparatus which conveys a sheet-like medium (hereinafter collectively referred to as “sheet”) such as paper and meanwhile forms an image on the sheet. The image forming apparatus is provided with a fixing device. The fixing device applies heat and pressure to the sheet to which the image is transferred to fix the image on the sheet. Thus, there is a possibility that the moisture contained in the sheet passing through the fixing device is evaporated, and as a result, the sheet is shrunk. The shrinkage degree of the sheet varies according to the category of the sheet. The shrunk sheet returns to the original size after a few minutes.
However, in a case of printing images on both sides of the sheet, there is a case in which the image is printed on the second surface before the sheet returns to the original size. As a result, when the sheet returns to the original size, the image printed on the second surface is stretched compared with the image printed on the first surface.